In order for two components to rotate relative to each other, they must be supported rotatably relative to each other, which as is known can be implemented for example by means of a plain bearing arrangement or a rolling bearing arrangement. As is known, lubrication for the bearing arrangement is required in order to minimize wear in the bearing arrangement. In order to actuate the rotary movement between the components, it is also necessary to involve a drive which, as is known, can be embodied for example by a gear transmission. If the gear transmission does not involve plastic gears which can only transmit low levels of torque, lubrication is required in the case of such a transmission in order to reduce wear.
As is known, lubricants are fed to the apparatus to provide the lubricating effect, more specifically either only when constructing the apparatus, this being known as so-called service life lubrication for example for rolling bearings, or at given intervals, which makes a respective maintenance intervention operation necessary, usually carried out by trained personnel.
At this juncture attention is directed generally to the following publications, as state of the art: DE 36 25 840 A1, DE 196 34 059 C1; DE 200 21 026 U1; DE 44 32 986 A1; DE 37 32 730 C1; and DE 44 44 535 A1. The above-indicated publications also inter alia cast light on the technological background of the present invention.
A particular situation of use of an apparatus for rotating two components relative to each other is an apparatus for rotating a rotor blade of a wind power installation about the longitudinal axis of the blade with respect to the rotor hub of the wind power installation for adjusting what is known as the pitch angle, that is to say the angle of incidence of the rotor blade with respect to the wind direction into which the rotor is oriented. Here, forces produced on the rotor blade by the wind exert a flexing moment of considerable magnitude on the bearing arrangement, which also adversely influences the wear aspect when rotary movement occurs. In addition, the rotary drive must produce a high rotating moment, not least because of those considerable flexing moments, and only a comparatively small amount of structural space is available for the rotary drive at the blade root where the bearing arrangement is also disposed. Because of the catastrophic consequences in the event of damage and consequential failure, for example because of excessive wear, the lubrication required both for the bearing arrangement and also for the rotary drive is particularly critical and therefore has to be carefully implemented. However, because of poor accessibility to the region to be lubricated, careful lubrication is also particularly complicated and expensive.